In this clip, which is making its exclusive premiere above, Collen — toting a guitar outfitted with a GoPro camera so you can see exactly what he's doing — looks back on a handful of the songs Def Leppard slaved over during the years it took to finish Hysteria. His comments shed a light on everything from the influences they absorbed while writing the songs — like "Armageddon It," which Collen says was inspired by T. Rex, and "Love Bites," which he recalls initially sounding like an Eagles song — to the incredible lengths they pursued to achieve sonic perfection.

"Animal," for instance, took three years to finish — and at one point, in order to hang onto a vocal take from singer Joe Elliott, the band and producer Mutt Lange opted to scrap the entire backing track and start over. And even after all that time — and millions of dollars in debt accrued to their record company — they were still willing to go one last extra mile after Lange heard Elliott fooling around on an acoustic guitar.

Recalling that they'd "kind of finished the album" by the time Lange happened upon Elliott in the midst of some fateful goofing off, Collen remembers the producer saying "we should make a song of this, we should record it" — and after a little push back, the band members ultimately acquiesced. Lange was proven right when that song, "Pour Some Sugar on Me," ended up becoming one of their all-time biggest hit singles.

"If you write songs based on the song, as opposed to the key, and you've got the melody in mind and that's where you go," Collen argues, "then all the other stuff falls into place."